It is one of golf’s paramount no-nos. Phil Mickelson says he’s well aware.

Yet on the par-four 13th at the U.S. Open at Shinnecock Hills Saturday, Mickelson ran down his bogey putt and struck the ball again while it was still moving. That violation is an automatic two-stroke penalty.

Wow. I've never seen that before.

Phil Mickelson ran after his putt before it stopped, which is a two stroke penalty.

Mickelson, 48, was already 10-over at the point. He carded a 10 on the hole for a 5 over par.

Mickelson has had a frustrating weekend at Shinnecock Hills, one of the more reviled major courses among pros. He finished Thursday with a 7-over par 77, which put him at the back of the field.

Friday was better — a 1-under 69 — but Saturday got off to an ugly start. He bogeyed holes Nos. 5, 8 and 9 on the front and followed that up with bogeys on Nos. 10 and 11, too.

“Look, I don’t mean disrespect by anybody,” Mickelson said on FOX Sports’ broadcast. “I know it’s a two-shot penalty. At that time, I didn’t feel like going back and forth and hitting the same shot over. I took the two-shot penalty and moved on. It’s my understanding of the rules. I’ve had multiple times where I’ve wanted to do that. I just finally did.”

“No question, it was going to go down off the green behind the bunker,” he continued. “I wasn’t going to have a shot. I don’t know if I would have been able to save a shot or not, but I know it’s a two-shot penalty, hitting a moving ball. I tried to hit it as close to the hole as I could to make the next one. You know, you take the two shots and you move on.”

His struggles on the course likely led to Saturday’s meltdown moment, but Twitter wasn’t giving Mickelson much slack.

It's now being called a 10 and thus is Mickelson's worst score on a U.S. Open hole as a pro. https://t.co/fCpq56dP0k

Phil Mickelson’s misstep at the US Open was the most stunning thing I’ve seen on a golf course since the time Happy Gilmore ripped off a guy’s shirt, punched him so hard that he rolled down a hill and then handed the guy’s shirt to another patron at the 1996 Waterbury Open.